Rotary-piston injection-type internal combustion engine

ABSTRACT

A rotary piston internal combustion engine, especially of trochoidal construction, in which a fuel injection valve is provided in the housing casing which injects fuel into the suction chamber of the engine, and in which a device is provided for lubricating the contact surface of the piston of the housing casing which is arranged downstream of the injection valve with respect to the direction of rotation of the piston.

United States Patent [191 Lamm [451 May 7,1974

ROTARY-PISTON INJECTION-TYPE INTERNAL COMBUSTION ENGINE [75] Inventor: Heinz Lamm, Esslingen-St.

' Bernhardt, Germany [73] Assignee: Daimler-Benz Aktiengesellschaft,

Stuttgart-Unterturkheim, Germany [22] Filed: Nov. 18, 1971 [21] Appl. No.: 199,921

(30] Foreign Application Priority Data Nov. 18, 1970 Germany 2056673 [52] U.S. C1 l23/8.09, 123/801, 418/97 [51] Int. Cl. F02b 53/10 [58] Field of Search 123/8.09, 8.13, 8.11, 8.45,

[56] References Cited UNITED STATES PATENTS Bentele l23/8.45

3,196,846 7/1965 Ohlendorf .1 l23/8.09 X

FOREIGN PATENTS OR APPLICATIONS 975,353 11/1964 Great Britain 123/8.l3

Primary Examiner-Carlton R. Croyle Assistant ExaminerMichael Koczo, Jr. Attorney, Agent, or Firm-Craig and Antonelli [5 7] ABSTRACT A rotary piston internal combustion engine, especially of trochoidal construction, in which a fuel injection valve is provided in the housing casing which injects fuel into the suction chamber of the engine, and in which a device is provided for lubricating the contact surface of the piston of the housing casing which is arranged downstream of the injection valve with respect to the direction of rotation of the piston.

6 Claims, 1 Drawing Figure ROTARY-PISTON INJECTION-TYPE INTERNAL COMBUSTION ENGINE The present invention relates to a rotary piston injection-type internal combustion engine, especially to an engine of trochoidal construction, in which are provided at the housing casing an injection valve injecting fuel into the suction chamber and an installation, by means of which the contact or running surface of the piston in the housing casing is lubricated.

l-Ieretofore with internal combustion engines of the type described above the lubricating oil for the lubrication of the contact surface of the piston in the housing casing is so supplied in metered quantities within the inlet channel or at the contact surface in proximity to the inlet channel that the lubricating oil adheres to the contact or running surface. This entails the disadvantage that the lubricating oil is supplied within the coldest zone of the entire internal combustion engine. Furthermore, this entails the disadvantage that a thinning of the lubricating oil takes place by the injected fuel or by condensation of the fuel.

The present invention is concerned with the task to avoid the described disadvantages.

The underlying problems are solved according to the present invention in that the installation for the lubrication of the contact surface is arranged downstream of the fuel injection valve in relation to the direction of rotation of the piston. Consequently, at first fuel and then only lubricating oil is supplied so that the lubricating oil is exposed to a lesser extent to the fuel. Additionally, the supply of lubricating oil takes place at a location, at which the housing casing is considerably warmer than, for example, within the area of the inlet channel opening. As a rule the feed location of lubrieating oil then lies within an area of the contact surface in which the sealing bars of the piston are forced with great force against the contact surface. The oil film at the contact surface is still fresh at this place. The lubrication and sealing therefore becomes more favorable. If fuel should reach the contact surface downstream of the injection valve, then the fuel evaporates more rapidly because the contact surface has a higher temperature.

In an advantageous embodiment of the inventive subject matter the installation for the lubrication may be arranged relatively close to the fuel injection valve. Furthermore, the installation for the lubrication may consist of a valve arranged near the contact surface which is connected with a conventional metering pump.

Accordingly, it is an object of the present invention to provide a rotary piston injection internal combustion engine which avoids the aforementioned shortcomings and drawbacks by simple means.

Another object of the present invention resides in a rotary piston internal combustion engine with fuel injection, which is characterized by an improved lubrication of the running surface of the housing casing.

A further object of the present invention resides in a rotary piston injection-type internal combustion engine which minimizes the danger of thinning of the lubricating oil by injected fuel or condensed fuel.

Another object of the present invention resides in a rotary piston injection-type internal combustion engine in which the lubricating oil is exposed to the fuel to a lesser extent.

These and further objects, features and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawing which shows, for pur poses of illustration only, oneembodiment in accordance with the present invention, and wherein The single FIGURE is a partial, somewhat schematic cross sectional view through a rotary piston internal combustion engine in accordance with the present invention in which the piston is omitted for the sake of simplicity.

Referring now to the single FIGURE of the drawing a conventional rotary piston internal combustion engine is illustrated in this FIGURE in cross section which includes a housing casing l and a piston 8 provided with radial sealing bars 9 in the piston corners thereof and rotating within the housing casing l in the direction of arrow 2. A fuel injection valve 4 is arranged in relation to the direction of rotation 2 of the piston downstream of the inlet channel 3 in the housing casing l of the rotary piston internal combustion engine, which injects fuel (gasoline) approximately in the direction of the discharge opening of the inlet channel 3 as indicated by-the fuel jet 41. In relation to the direction of rotation 2 of the piston (not shown) a conventional lubricating valve 5 is disposed in thehousing casing l, downstream of the injection valve 4 at a slight distance therefrom, which lubricating valve 5 is connected with a conventional metering pump 10 by way of a line 11 and whose discharge orifice 5' is disposed close to the contact or running surface 6 for the piston at the housing casing l. The suction side of the pump 10 is connected with the lubricating oil supply schematically indicated by reference numeral 12.

Lubricating oil is fed by the metering pump 10- to the lubricating valve 5 which opens with supplied lubricating oil under pressure and releases a predetermined amount of lubricating oil that distributes itself over the running or contact surface 6 in the direction of rotation 2 of the piston. Since the lubricating valve 5 is located between the injection valve 4 and the sparkplug 7, i.e., within an already relatively warm area of the housing casing 1, the lubrication is very good so that'in particular high contact-surface wear and high sealing-bar wear, which otherwise occur within this area, are avoided. If the lubricating film at the contact surface 6 should come in contact with fuel, then the fuel evaporates rapidly. US. Pat. No. 2,778,539 discloses a fuel metering device which could be used as the metering pump and conventional lubricating valve with the present invention.

While I have shown and described only one embodiment in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to those skilled in the art and I therefore do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

What I claim is:

l. A rotary piston internal combustion engine with fuel injection, comprising a housing means with a housing casing provided with a contact surface, a rotatable piston sliding with its piston corners along said contact surface, and an injection valve means provided in said housing means for injecting fuel into a suction chamber formed between said housing casing and said piston, and in which a lubricating means is also provided for lubricating the contact surface of the piston provided in the housing casing, characterized in that the lubricating means for the lubrication of the contact surface is arranged downstream of the injection valve means in relation to the direction of rotation of the piston, and characterized in that the lubricating means includes a lubricating valve having a discharge orifice arranged slightly recessed in said housing casing relative to said contact surface.

2. An internal'combustion engine according to claim 1 characterized in that the lubricating means consists fof a valvearranged near the contact surface which is operatively connected with a metering pump.

3. A rotary piston internal combustion engine according to claim 1 characterized in that the engine is of trochoidal construction.

4. A rotary piston internal combustion engine with an inlet channel in said housing means for combustion air according to claim 1, characterized in that the fuel is injected by said injection valve means approximately in the direction toward said inlet channel.

5. A rotary piston internal combustion engine according to claim 4 wherein said fuel is gasoline;

6. An internal combustion engine according to claim 5, characterized in that the lubricating means is arranged relatively close to the injection valve means. 

1. A rotary piston internal combustion engine with fuel injection, comprising a housing means with a housing casing provided with a contact surface, a rotatable piston sliding with its piston corners along said contact surface, and an injection valve means provided in said housing means for injecting fuel into a suction chamber formed between said housing casing and said piston, and in which a lubricating means is also provided for lubricating the contact surface of the piston provided in the housing casing, characterized in that the lubricating means for the lubrication of the contact surface is arranged downstream of the injection valve means in relation to the direction of rotation of the piston, and characterized in that the lubricating means includes a lubricating valve having a discharge orifice arranged slightly recessed in said housing casing relative to said contact surface.
 2. An internal combustion engine according to claim 1 characterized in that the lubricating means consists of a valve arranged near the contact surface which is operatively connected with a metering pump.
 3. A rotary piston internal combustion engine according to claim 1 characterized in that the engine is of trochoidal construction.
 4. A rotary piston internal combustion engine with an inlet channel in said housing means for combustion air according to claim 1, characterized in that the fuel is injected by said injection valve means approximately in the direction toward said inlet channel.
 5. A rotary piston internal combustion engine according to claim 4 wherein said fuel is gasoline.
 6. An internal combustion engine according to claim 5, characterized in that the lubricating means is arranged relatively close to the injection valve means. 